/* Copyright (c) 2010, Carl Burch. License information is located in the
 * com.cburch.logisim.Main source code and at www.cburch.com/logisim/. */

package com.cburch.logisim.std.arith;

import java.awt.Color;
import java.awt.Graphics;

import com.cburch.logisim.data.Attribute;
import com.cburch.logisim.data.BitWidth;
import com.cburch.logisim.data.Bounds;
import com.cburch.logisim.data.Direction;
import com.cburch.logisim.data.Location;
import com.cburch.logisim.data.Value;
import com.cburch.logisim.instance.InstanceFactory;
import com.cburch.logisim.instance.InstancePainter;
import com.cburch.logisim.instance.InstanceState;
import com.cburch.logisim.instance.Port;
import com.cburch.logisim.instance.StdAttr;
import com.cburch.logisim.tools.key.BitWidthConfigurator;
import com.cburch.logisim.util.GraphicsUtil;
import static com.cburch.logisim.util.LocaleString.*;

public class Divider extends InstanceFactory {
    static final int PER_DELAY = 1;

    private static final int IN0   = 0;
    private static final int IN1   = 1;
    private static final int OUT   = 2;
    private static final int UPPER = 3;
    private static final int REM   = 4;

    public Divider() {
        super("Divider", getFromLocale("dividerComponent"));
        setAttributes(new Attribute[] { StdAttr.WIDTH },
                new Object[] { BitWidth.create(8) });
        setKeyConfigurator(new BitWidthConfigurator(StdAttr.WIDTH));
        setOffsetBounds(Bounds.create(-40, -20, 40, 40));
        setIconName("divider.svg");

        Port[] ps = new Port[5];
        ps[IN0]   = new Port(-40, -10, Port.INPUT,  StdAttr.WIDTH);
        ps[IN1]   = new Port(-40,  10, Port.INPUT,  StdAttr.WIDTH);
        ps[OUT]   = new Port(  0,   0, Port.OUTPUT, StdAttr.WIDTH);
        ps[UPPER] = new Port(-20, -20, Port.INPUT,  StdAttr.WIDTH);
        ps[REM]   = new Port(-20,  20, Port.OUTPUT, StdAttr.WIDTH);
        ps[IN0].setToolTip(getFromLocale("dividerDividendLowerTip"));
        ps[IN1].setToolTip(getFromLocale("dividerDivisorTip"));
        ps[OUT].setToolTip(getFromLocale("dividerOutputTip"));
        ps[UPPER].setToolTip(getFromLocale("dividerDividendUpperTip"));
        ps[REM].setToolTip(getFromLocale("dividerRemainderTip"));
        setPorts(ps);
    }

    @Override
    public void propagate(InstanceState state) {
        // get attributes
        BitWidth dataWidth = state.getAttributeValue(StdAttr.WIDTH);

        // compute outputs
        Value a = state.getPort(IN0);
        Value b = state.getPort(IN1);
        Value upper = state.getPort(UPPER);
        Value[] outs = Divider.computeResult(dataWidth, a, b, upper);

        // propagate them
        int delay = dataWidth.getWidth() * (dataWidth.getWidth() + 2) * PER_DELAY;
        state.setPort(OUT, outs[0], delay);
        state.setPort(REM, outs[1], delay);
    }

    @Override
    public void paintInstance(InstancePainter painter) {
        Graphics g = painter.getGraphics();
        painter.drawBounds();

        g.setColor(Color.GRAY);
        painter.drawPort(IN0);
        painter.drawPort(IN1);
        painter.drawPort(OUT);
        painter.drawPort(UPPER, getFromLocale("dividerUpperInput"),  Direction.NORTH);
        painter.drawPort(REM, getFromLocale("dividerRemainderOutput"), Direction.SOUTH);

        Location loc = painter.getLocation();
        int x = loc.getX();
        int y = loc.getY();
        GraphicsUtil.switchToWidth(g, 2);
        g.setColor(Color.BLACK);
        g.fillOval(x - 12, y - 7, 4, 4);
        g.drawLine(x - 15, y, x - 5, y);
        g.fillOval(x - 12, y + 3, 4, 4);
        GraphicsUtil.switchToWidth(g, 1);
    }

    static Value[] computeResult(BitWidth width, Value a, Value b, Value upper) {
        int w = width.getWidth();
        if (upper == Value.NIL || upper.isUnknown()) {
            upper = Value.createKnown(width, 0);
        }

        if (a.isFullyDefined() && b.isFullyDefined() && upper.isFullyDefined()) {
            long num = ((long) upper.toIntValue() << w)
                | (a.toIntValue() & 0xFFFFFFFFL);
            long den = b.toIntValue() & 0xFFFFFFFFL;
            if (den == 0) {
                den = 1;
            }

            long result = num / den;
            long rem = num % den;
            if (rem < 0) {
                if (den >= 0) {
                    rem += den;
                    result--;
                } else {
                    rem -= den;
                    result++;
                }
            }
            return new Value[] { Value.createKnown(width, (int) result),
                    Value.createKnown(width, (int) rem) };
        } else if (a.isErrorValue() || b.isErrorValue() || upper.isErrorValue()) {
            return new Value[] { Value.createError(width), Value.createError(width) };
        } else {
            return new Value[] { Value.createUnknown(width), Value.createUnknown(width) };
        }
    }
}
